This application claims the benefit of Korean Application No. 200074761, filed on Dec. 8, 2000 in the Korean Patent Office, the entire disclosure of which is incorporated herein by reference.
The present invention relates to a color selection apparatus for a cathode ray tube (CRT), and more particularly, to a color selection apparatus that can be employed with a CRT having a flat screen panel.
In recent years, a cathode ray tube having a flat panel on which a screen is formed has been developed as a display and widely used. That is, because users wish to see an image on a large-sized display, such as a color TV and a computer monitor, a screen panel of a CRT used for color TV""s and computer monitor""s has increased in size. As the size of the panel is increased, a technology for forming the panel to be flat has been developed in consideration of images realized at the peripheral region of the screen panel.
As the screen panel is enlarged and flattened, a color selection apparatus having a tension mask for realizing the color is also enlarged. However, when the color selection apparatus is enlarged, a variety of problems, including a rigidity problem, occur. Therefore, new designs of the color selection apparatus have been employed.
Namely, a tension mask having a plurality of apertures through which electron beams pass is designed to be flat rather than formed having a curvature radius. The tension mask is applied with a predetermined tension. A color selection apparatus having such a flat tension mask is disclosed in U.S. Pat. Nos. 5,416,380 and 5,550,428. FIG. 6 shows a conventional color selection apparatus having such a flat tension mask. As shown in the drawing, a color selection apparatus comprises a pair of elastic members 2 and 4, a pair of supporting members 6 and 8 respectively coupled to the elastic members 2 and 4, and a flat mask 10 supported by the supporting members 6 and 8 and provided with a plurality of electron beam passing apertures 10a. 
Each of the elastic members 2 and 4 are spaced away from each other and are formed in a U-shape using a hollow tube member. The supporting members 6 and 8 are arranged in parallel in a longitudinal direction of the mask 10. Opposite ends of each of the supporting members 6 and 8 are respectively fixed on ends of the respective elastic members 2 and 4 using a welding process.
The flat mask 10 is welded on the supporting members 6 and 8, and it maintains its predetermined tension according to the movement of the elastic members 2 and 4.
The above-described color selection apparatus is mounted inside the panel of the CRT so as to select a color when electron beams are radiated from an electron gun.
A hole 2a is formed passing through each side of the elastic members 2 and 4. The holes 2a are covered with a steel plate 12 having a predetermined thickness. During the welding process for coupling the elastic members 2 and 4 to the supporting members 6 and 8, a welding gas may flow into the hollow-shaped elastic members 2 and 4. The holes 2a function as a gas exhaust hole for exhausting such a gas out of the elastic members 2 and 4.
The holes 2a are temporally blocked by, for example, nails, during the assembling process of the color selection apparatus after the welding process. The holes 2a are then permanently blocked by the steel plate 12 after the assembling process.
The temporary blocking of the holes 2a, using, for example, nails, is to prevent cleansing agents from flowing into the elastic members 2 and 4 through the holes during the cleansing process of the color selection apparatus. Since the hollow elastic members 2 and 4 are sealed when they are coupled to the supporting members 6 and 8, if the cleansing agent flows into the elastic members 2 and 4 and the hole 2a is too small, the cleansing agent may not be completely drained out of the elastic members 2 and 4.
In addition, the permanent blocking of the elastic members 2 and 4 using the steel plates 12 after the assembling process is to prevent alien substances, such as iron filings and dust, remaining in the hollow elastic members 2 and 4 from getting out during the exhaust process of the CRT where the color selection apparatus is mounted. If the alien substances get out of the elastic members 2 and 4, the alien substances may block the electron beam passing holes or be attached to the electron gun, thereby deteriorating the performance of the CRT.
As described above, due to the structure of the color selection apparatus, the CRT is manufactured through many processes to improve its performance. Therefore, many apparatuses for each process are required. This causes a deterioration of productivity and an increase in manufacturing costs. Therefore, there is a need for an improved structure of a color selection apparatus that can simplify the manufacturing process of a CRT, thereby improving productivity and reducing manufacturing costs.
To meet the above need, the present invention provides a color selection apparatus with a frame having a pair of supporting members disposed in parallel with each other, and a pair of elastic members disposed between, and coupled to, the supporting members. Each of the elastic members is formed of a hollow tube. A mask is coupled to the supporting members while being applied with a predetermined tension. The color selection apparatus also has a means for exhausting remaining alien substances from within the elastic members during an assembling process of the color selection apparatus, the means for exhausting being formed on each of the elastic members at a portion adjacent to where the elastic members are coupled to the supporting members.
According to a first embodiment of the present invention, the means for exhausting comprises a cut-away portion formed such that an inside of each elastic member is opened to an outside.
According to a second embodiment of the present invention, the means for exhausting comprises opened opposite ends of each elastic member, a part of each of the opened opposite ends maintaining its open state even after the opened opposite ends are coupled to the supporting members.